The cabbages in my allotment when cooked taste bitter, why?

Question

The cabbages in my allotment when cooked taste bitter, why?

Answer 1

slug sperm

Answer 2

Probably the soil type, try a bit of litmus paper in the ground around the cabbages.

If acidic, a very small amount of lime would help.

If alkaline, any citric acid would help.

Depends on the plant as well, but I think cabbages like something fairly neutral